Data compression has become a necessity in the ever growing need for data transfer, on the Internet, voice communications, and video transmission. In essence, data compression attempts to compress information in the smallest amount of data for minimizing disk space storage and for reducing bandwidth requirements during data transmission. Telephone, and video-conferencing services are perhaps the best known services which compress data in an attempt to maximize channel or leased line usage. Moreover, communications equipment such as modems, multiplexers, routers and bridges utilize compression techniques to improve data throughput over various communications medium.
Many compression techniques compress data by minimizing the number of bits necessary to represent the data. For example, ASCII encoded data uses a 7-bit or 8-bit code set, however during transmission of this data, a reduced 3-bit code set can often be used to transmit some of the most common characters. Moreover, data transmission is often filled with blank or meaningless data which can be replaced by data representative of the amount of blank data which needs to be transmitted. For example, in audio data, silence may be represented by data representative of the length of the silence—in video transmission, white space may be represented by data representative of the amount of white space.
These compression techniques employ both lossless and lossy compression schemes which either attempt to faithfully reproduce the original data or attempt to reproduce most of the data or substantially similar data with an accepted and known amount of data loss. In a lossy compression scheme, the original data can never be recovered exactly, while in a lossless scheme, the original and exact data is reproduced. Both schemes have advantages and disadvantages and are employed according to the needs of the recipient.
Although lossy compression schemes have been applied to the transmission of analog data, there remains a need for a method and system which compresses analog data in a more efficient manner for both storage and transmission. The present invention address this need by enhancing analog data compression by utilizing the slopes of previous and next data values from the point of reference of a last stored data value.